Glass stock for electric melting



March 4, 1941. H. SNOW GLASS s'rocx Fox ELECTRIC MELTINQ Filed Feb. 26,1938 INVEN TOR HENRY Amw.

Poema Misc 1941 2,233,435

UNITED vSTATES PATENT OFFICE v GLASS STOCK FOR ELECTRIC Henry Snow,Newark, Ohio, assiznor, by mesne assignments, to Owens-Corning FiberglasCorporation, Toledo, Ohio, a corporation ot Delaware ApplicationFebruary 26, 1938, Serial No. 192,689

4 Claims. (Cl. 49-77) The present invention relates to a form of glassstock prior to its melting in and becoming part stock which may be fedinto a supply body of of the molten body. molten glass and form a partthereof, and more Another object of the invention is to facilitateparticularly to a formo! suchv glass stock which feeding of the glassstock into theviurnace. maybe' melted and yreadily pass into said bodyStill another object of the invention is to rewhileat a relativelylowtemperature, or at a duce the amount of heating necessary to melttemperaturebelow which lining and elimination the glass stock in orderto orm a supply body of trapped gases may readily take place. at theproper temperature and free from seeds.

i Among the objects of the present invention is It is also the aim ofthe invention to reduce the l primarily to procure seed-free glass. Theuses of size oi the melting containers over that necessuch glass mayV bemanifold, but such glass is sary for other types o glass stock.particularly desirable when producing optical Other objects andadvantages of the present glassor fibrous glass for textile purposes insmall invention will become apparent from the folbushings or troughswhich are electrically ,heatlowing description taken in conjunction with`V ed in order to melt the glass therein. the drawing, in which:

The temperature of such glass is relatively Fig. l is a cross-sectionalelevational view of critical in order to produce iibrous glass of a higha melting unit as applied to an apparatus for proquality. Thistemperature generally is below the ducing :fibrous glass; andnin'g'temberature of the glass, or at least is at Fig. 2 is a. plan viewof the same apparatus.

a temperature at which nlng and elimination The present invention isbased in part upon of gas bubbles, seeds and the like is sluggish. thediscovery that tempered glass. that is glass Accordingly, if any stones,air bubbles or seeds having internal strains, and especially strains areentrap'ped in this molten body, they are preproducing a surfacecompression, has a melting vented from rising to the surface of theglass characteristic unlike other glasses, in that as it and escaping.Instead they dow downwardly with melts, it merely slumps and merges intothe supthe molten body to the outlet openings where ply body withoutcracking, crizzling, or otherthey interrupt the ow of the glass andcause `Wise breaking up. whereby gases, seeds and bubdiscontinu'ltiesin` the glass streams. Such disbles are preventedv from becomingentrained in continuities cause much difficulty in the operathe supplybody. It is also possible when melting tion, and lower the emciency andquality of the tempered or strained glass, to melt the same at finishedproduct. a lower temperature and form the supply body In order toprovide a smooth supply body of at a lower temperature, in View of thefact that glass free from stones and seeds, it has been it isunnecessary to remelt or rework the glass found advisable to iced inreined glass cullet or at a high temperature in order to permit seeds,glass stock. bubbles or the like from escaping into the at- Ordinaryglass stock or cullet has been found mosphere. to crizzleor crack upduring the melting period Another phaseof the .invention involves theowing to:uneven melting conditions, and tiny use o! rounded surfaces andespecially glass bubbles and seeds are carried into the molten balls orspheres which lend themselves admirably glass in the cracks or cxizzledportions thereof. to the present invention. The use of glass balls Theseentrained gases are difdcult, if not imposor spheres facilitates theformation of uniformly sible to remove. As a matter of fact, ordinarytempered or strained glass. Moreover, the sizes annealed glass culletbecomes so strained in the of the spheres may b e uniform and thusinsure furnace during the melting period, that it may a positive amountof eglass feed, regulable merecrack with violence. In order to partiallyoverly by adjusting the interval of time of feeding 15` come thiscondition heretofore, it has been necesof the glass balls.

sary to heat the glass to high -temperatures Another highly advantageousfeature of the to render the glass very iiuid, and then cool it to glassballs is that they automatically magnify the desired forming range, butthis used an exany defects such as seeds or stones carried therecessiveamount of heat and necessitated a larger in and thus facilitateinspection.

melting unit. Glass bodies having rounded surfaces may be An object ofthe present invention is to over-` made from cane or pressed plates, orif spheres come these objections, and to provide glass stock 'are usedthey may be fabricated on ordinary marin a form which will preventcracking or crizzling ble machines. The sizes of the glass bodies mayduring the heating up and melting period of the vary considerablyranging from shot-like particles to large bodies, although it has beenfound that for ordinary textile bushings sizes of about 1A to 1 inch indiameter are satisfactory.

Referring now more particularly to the drawing, reference character 8designates a melting crucible, preferably ct metal such as platinum orthe like, although other metals of Nichrme, iron or the 'like may alsobe used. It desired, an

ordinary clay crucible, forehearth, tank or the like may also be used.

The cruci-ble 5 is provided at the lower end thereof with a series oi.'outlet orifices 6 adapted to emit glass for any desired purpose. Thecrucible is held in a suitable refractory support 'l which may be heldby the framework l. The metal crucible or container 5 is preferablyelectrically heated, as by a transformer Il or other suitable source ofelectrical energy. The transformer is electrically connected through theterminals Ii to lugs l2 integral with and on each side of the container5.

The crucible 5 contains a body i5 o! molten glass, which is replenishedand regulated by glass stock I6, produced in accordance with the presentinvention. As shown in the drawing, the glass stock I8 is in the form ofspheres which are fed to the top of the molten body I5 where they aregradually heated by the molten body and gradually slump, m'elt and formpart of the body. Reference character Isa designates a body of glassstock having rounded surfaces and which may be made from cane, orpressed plate or the like and suitably provided with internal strains.The glass stock article l1 is shown partially melted into the supply'body f5. It will be noted that during the melting these particles donot crack and entrain gaseous bubbles or the likeV Athe glass to bemelted at temperatures below which ning and removal of gas, bubbles orthe aaasyiss l like is readily and practieably accomplished. Othershapes of tempered glass bodies having rounded surfaces. such ascylinders. produced from cane or thelike may also be used.

'Various modifications and variations may be 5 rewrted to within thespirit` and scope ci the present invention as deilned in the appendedclaims.,

I claim: ,i

1. The method of maintaining for the producl( tion of ilbrous glass abody oi' molten. glass at a viscosity at which the removal of bubblesand seeds and the'fmelting and fusing into a homogeneous body issluggish which comprises feeding into said body seed-free glass stock ina vitrifledl 1g state and in the form ot spheres having compressionstrains in the periphery thereon 2. 'Ihe method of maintaining for theproduction of fibrous glass a body of molten glass and maintaining thesame at a viscosity at which the 24 removal of bubbles and seeds and themelting and fusing into a homogeneous body is sluggish, which oom-prisesfeeding into said body seed-freev glass stock bodies in a vitriileclstate of highly tempered internally strained glass having round- 2; edsurfaces and substantially no sharp edges or cracks.

3. In the method of producing fibrous glass, the steps ci establishing amolten supply body of glass at a temperature at which removal of 3(seeds and gaseous bubbles is sluggish. discharging .streams of glasscontinually from said supply body for attenuating them into bers, andreplenishing said supply body by feeding into said Vsupply body glassstock of internally strained 35 glass spheres. p

4;. The method of melting glass for use in forming filaments whichcomprises forming glass into substantially spherical shapes andimparting strains therein, feeding said shapes into a fur 4( nace andmelting said shapes in the furnace.

HENRY snow.

